[PATCH 1/2] xfs: teach scrub to check for sole ownership of metadata objects

Darrick J. Wong
2022-12-30T22:44:40Z

Strengthen online scrub's checking even further by enabling us to check
that a range of blocks are owned solely by a given owner.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/libxfs/xfs_rmap.c | 198 ++++++++++++++++++++++++++++++++--------------
fs/xfs/libxfs/xfs_rmap.h | 18 +++-
fs/xfs/scrub/agheader.c | 10 +-
fs/xfs/scrub/btree.c | 2
fs/xfs/scrub/ialloc.c | 4 -
fs/xfs/scrub/inode.c | 2
fs/xfs/scrub/rmap.c | 45 ++++++----
fs/xfs/scrub/scrub.h | 2
8 files changed, 185 insertions(+), 96 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
index 308b81f321eb..a9f13d877822 100644
--- a/fs/xfs/libxfs/xfs_rmap.c
+++ b/fs/xfs/libxfs/xfs_rmap.c
@@ -2735,65 +2735,141 @@ xfs_rmap_has_records(
return xfs_btree_has_records(cur, &low, &high, &mask, outcome);
}

-/*
- * Is there a record for this owner completely covering a given physical
- * extent? If so, *has_rmap will be set to true. If there is no record
- * or the record only covers part of the range, we set *has_rmap to false.
- * This function doesn't perform range lookups or offset checks, so it is
- * not suitable for checking data fork blocks.
- */
-int
-xfs_rmap_record_exists(
- struct xfs_btree_cur *cur,
- xfs_agblock_t bno,
- xfs_extlen_t len,
- const struct xfs_owner_info *oinfo,
- bool *has_rmap)
-{
- uint64_t owner;
- uint64_t offset;
- unsigned int flags;
- int has_record;
- struct xfs_rmap_irec irec;
- int error;
+struct xfs_rmap_ownercount {
+ /* Owner that we're looking for. */
+ struct xfs_rmap_irec good;

- xfs_owner_info_unpack(oinfo, &owner, &offset, &flags);
- ASSERT(XFS_RMAP_NON_INODE_OWNER(owner) ||
- (flags & XFS_RMAP_BMBT_BLOCK));
+ /* rmap search keys */
+ struct xfs_rmap_irec low;
+ struct xfs_rmap_irec high;

- error = xfs_rmap_lookup_le(cur, bno, owner, offset, flags, &irec,
- &has_record);
- if (error)
- return error;
- if (!has_record) {
- *has_rmap = false;
- return 0;
- }
+ struct xfs_rmap_matches *results;

- *has_rmap = (irec.rm_owner == owner && irec.rm_startblock <= bno &&
- irec.rm_startblock + irec.rm_blockcount >= bno + len);
- return 0;
-}
-
-struct xfs_rmap_key_state {
- uint64_t owner;
- uint64_t offset;
- unsigned int flags;
+ /* Stop early if we find a nonmatch? */
+ bool stop_on_nonmatch;
};

-/* For each rmap given, figure out if it doesn't match the key we want. */
+/* Does this rmap represent space that can have multiple owners? */
+static inline bool
+xfs_rmap_shareable(
+ struct xfs_mount *mp,
+ const struct xfs_rmap_irec *rmap)
+{
+ if (!xfs_has_reflink(mp))
+ return false;
+ if (XFS_RMAP_NON_INODE_OWNER(rmap->rm_owner))
+ return false;
+ if (rmap->rm_flags & (XFS_RMAP_ATTR_FORK |
+ XFS_RMAP_BMBT_BLOCK))
+ return false;
+ return true;
+}
+
+static inline void
+xfs_rmap_ownercount_init(
+ struct xfs_rmap_ownercount *roc,
+ xfs_agblock_t bno,
+ xfs_extlen_t len,
+ const struct xfs_owner_info *oinfo,
+ struct xfs_rmap_matches *results)
+{
+ memset(roc, 0, sizeof(*roc));
+ roc->results = results;
+
+ roc->low.rm_startblock = bno;
+ memset(&roc->high, 0xFF, sizeof(roc->high));
+ roc->high.rm_startblock = bno + len - 1;
+
+ memset(results, 0, sizeof(*results));
+ roc->good.rm_startblock = bno;
+ roc->good.rm_blockcount = len;
+ roc->good.rm_owner = oinfo->oi_owner;
+ roc->good.rm_offset = oinfo->oi_offset;
+ if (oinfo->oi_flags & XFS_OWNER_INFO_ATTR_FORK)
+ roc->good.rm_flags |= XFS_RMAP_ATTR_FORK;
+ if (oinfo->oi_flags & XFS_OWNER_INFO_BMBT_BLOCK)
+ roc->good.rm_flags |= XFS_RMAP_BMBT_BLOCK;
+}
+
+/* Figure out if this is a match for the owner. */
STATIC int
-xfs_rmap_has_other_keys_helper(
+xfs_rmap_count_owners_helper(
struct xfs_btree_cur *cur,
const struct xfs_rmap_irec *rec,
void *priv)
{
- struct xfs_rmap_key_state *rks = priv;
+ struct xfs_rmap_ownercount *roc = priv;
+ struct xfs_rmap_irec check = *rec;
+ unsigned int keyflags;
+ bool filedata;
+ int64_t delta;

- if (rks->owner == rec->rm_owner && rks->offset == rec->rm_offset &&
- ((rks->flags & rec->rm_flags) & XFS_RMAP_KEY_FLAGS) == rks->flags)
- return 0;
- return -ECANCELED;
+ filedata = !XFS_RMAP_NON_INODE_OWNER(check.rm_owner) &&
+ !(check.rm_flags & XFS_RMAP_BMBT_BLOCK);
+
+ /* Trim the part of check that comes before the comparison range. */
+ delta = (int64_t)roc->good.rm_startblock - check.rm_startblock;
+ if (delta > 0) {
+ check.rm_startblock += delta;
+ check.rm_blockcount -= delta;
+ if (filedata)
+ check.rm_offset += delta;
+ }
+
+ /* Trim the part of check that comes after the comparison range. */
+ delta = (check.rm_startblock + check.rm_blockcount) -
+ (roc->good.rm_startblock + roc->good.rm_blockcount);
+ if (delta > 0)
+ check.rm_blockcount -= delta;
+
+ /* Don't care about unwritten status for establishing ownership. */
+ keyflags = check.rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK);
+
+ if (check.rm_startblock == roc->good.rm_startblock &&
+ check.rm_blockcount == roc->good.rm_blockcount &&
+ check.rm_owner == roc->good.rm_owner &&
+ check.rm_offset == roc->good.rm_offset &&
+ keyflags == roc->good.rm_flags) {
+ roc->results->matches++;
+ } else {
+ roc->results->nono_matches++;
+ if (xfs_rmap_shareable(cur->bc_mp, &roc->good) ^
+ xfs_rmap_shareable(cur->bc_mp, &check))
+ roc->results->badno_matches++;
+ }
+
+ if (roc->results->nono_matches && roc->stop_on_nonmatch)
+ return -ECANCELED;
+
+ return 0;
+}
+
+/* Count the number of owners and non-owners of this range of blocks. */
+int
+xfs_rmap_count_owners(
+ struct xfs_btree_cur *cur,
+ xfs_agblock_t bno,
+ xfs_extlen_t len,
+ const struct xfs_owner_info *oinfo,
+ struct xfs_rmap_matches *results)
+{
+ struct xfs_rmap_ownercount roc;
+ int error;
+
+ xfs_rmap_ownercount_init(&roc, bno, len, oinfo, results);
+ error = xfs_rmap_query_range(cur, &roc.low, &roc.high,
+ xfs_rmap_count_owners_helper, &roc);
+ if (error)
+ return error;
+
+ /*
+ * There can't be any non-owner rmaps that conflict with the given
+ * owner if we didn't find any rmaps matching the owner.
+ */
+ if (!results->matches)
+ results->badno_matches = 0;
+
+ return 0;
}

/*
@@ -2806,28 +2882,26 @@ xfs_rmap_has_other_keys(
xfs_agblock_t bno,
xfs_extlen_t len,
const struct xfs_owner_info *oinfo,
- bool *has_rmap)
+ bool *has_other)
{
- struct xfs_rmap_irec low = {0};
- struct xfs_rmap_irec high;
- struct xfs_rmap_key_state rks;
+ struct xfs_rmap_matches res;
+ struct xfs_rmap_ownercount roc;
int error;

- xfs_owner_info_unpack(oinfo, &rks.owner, &rks.offset, &rks.flags);
- *has_rmap = false;
+ xfs_rmap_ownercount_init(&roc, bno, len, oinfo, &res);
+ roc.stop_on_nonmatch = true;

- low.rm_startblock = bno;
- memset(&high, 0xFF, sizeof(high));
- high.rm_startblock = bno + len - 1;
-
- error = xfs_rmap_query_range(cur, &low, &high,
- xfs_rmap_has_other_keys_helper, &rks);
+ error = xfs_rmap_query_range(cur, &roc.low, &roc.high,
+ xfs_rmap_count_owners_helper, &roc);
if (error == -ECANCELED) {
- *has_rmap = true;
+ *has_other = true;
return 0;
}
+ if (error)
+ return error;

- return error;
+ *has_other = false;
+ return 0;
}

const struct xfs_owner_info XFS_RMAP_OINFO_SKIP_UPDATE = {
diff --git a/fs/xfs/libxfs/xfs_rmap.h b/fs/xfs/libxfs/xfs_rmap.h
index 4cbe50cf522e..ced605d69324 100644
--- a/fs/xfs/libxfs/xfs_rmap.h
+++ b/fs/xfs/libxfs/xfs_rmap.h
@@ -200,12 +200,24 @@ xfs_failaddr_t xfs_rmap_check_irec(struct xfs_btree_cur *cur,

int xfs_rmap_has_records(struct xfs_btree_cur *cur, xfs_agblock_t bno,
xfs_extlen_t len, enum xbtree_recpacking *outcome);
-int xfs_rmap_record_exists(struct xfs_btree_cur *cur, xfs_agblock_t bno,
+
+struct xfs_rmap_matches {
+ /* Number of owner matches. */
+ unsigned long long matches;
+
+ /* Number of non-owner matches. */
+ unsigned long long nono_matches;
+
+ /* Number of non-owner matches that conflict with the owner matches. */
+ unsigned long long badno_matches;
+};
+
+int xfs_rmap_count_owners(struct xfs_btree_cur *cur, xfs_agblock_t bno,
xfs_extlen_t len, const struct xfs_owner_info *oinfo,
- bool *has_rmap);
+ struct xfs_rmap_matches *rmatch);
int xfs_rmap_has_other_keys(struct xfs_btree_cur *cur, xfs_agblock_t bno,
xfs_extlen_t len, const struct xfs_owner_info *oinfo,
- bool *has_rmap);
+ bool *has_other);
int xfs_rmap_map_raw(struct xfs_btree_cur *cur, struct xfs_rmap_irec *rmap);

extern const struct xfs_owner_info XFS_RMAP_OINFO_SKIP_UPDATE;
diff --git a/fs/xfs/scrub/agheader.c b/fs/xfs/scrub/agheader.c
index 520ec054e4a6..75de0ba4fcef 100644
--- a/fs/xfs/scrub/agheader.c
+++ b/fs/xfs/scrub/agheader.c
@@ -51,7 +51,7 @@ xchk_superblock_xref(

xchk_xref_is_used_space(sc, agbno, 1);
xchk_xref_is_not_inode_chunk(sc, agbno, 1);
- xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
+ xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
xchk_xref_is_not_shared(sc, agbno, 1);
xchk_xref_is_not_cow_staging(sc, agbno, 1);

@@ -515,7 +515,7 @@ xchk_agf_xref(
xchk_agf_xref_freeblks(sc);
xchk_agf_xref_cntbt(sc);
xchk_xref_is_not_inode_chunk(sc, agbno, 1);
- xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
+ xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
xchk_agf_xref_btreeblks(sc);
xchk_xref_is_not_shared(sc, agbno, 1);
xchk_xref_is_not_cow_staging(sc, agbno, 1);
@@ -644,7 +644,7 @@ xchk_agfl_block_xref(

xchk_xref_is_used_space(sc, agbno, 1);
xchk_xref_is_not_inode_chunk(sc, agbno, 1);
- xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_AG);
+ xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_AG);
xchk_xref_is_not_shared(sc, agbno, 1);
xchk_xref_is_not_cow_staging(sc, agbno, 1);
}
@@ -701,7 +701,7 @@ xchk_agfl_xref(

xchk_xref_is_used_space(sc, agbno, 1);
xchk_xref_is_not_inode_chunk(sc, agbno, 1);
- xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
+ xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
xchk_xref_is_not_shared(sc, agbno, 1);
xchk_xref_is_not_cow_staging(sc, agbno, 1);

@@ -857,7 +857,7 @@ xchk_agi_xref(
xchk_xref_is_used_space(sc, agbno, 1);
xchk_xref_is_not_inode_chunk(sc, agbno, 1);
xchk_agi_xref_icounts(sc);
- xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
+ xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
xchk_xref_is_not_shared(sc, agbno, 1);
xchk_xref_is_not_cow_staging(sc, agbno, 1);
xchk_agi_xref_fiblocks(sc);
diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c
index 8ae42dff632f..24ea77e46ebd 100644
--- a/fs/xfs/scrub/btree.c
+++ b/fs/xfs/scrub/btree.c
@@ -402,7 +402,7 @@ xchk_btree_check_block_owner(
if (!bs->sc->sa.bno_cur && btnum == XFS_BTNUM_BNO)
bs->cur = NULL;

- xchk_xref_is_owned_by(bs->sc, agbno, 1, bs->oinfo);
+ xchk_xref_is_only_owned_by(bs->sc, agbno, 1, bs->oinfo);
if (!bs->sc->sa.rmap_cur && btnum == XFS_BTNUM_RMAP)
bs->cur = NULL;

diff --git a/fs/xfs/scrub/ialloc.c b/fs/xfs/scrub/ialloc.c
index 598112471d07..f690143af0c0 100644
--- a/fs/xfs/scrub/ialloc.c
+++ b/fs/xfs/scrub/ialloc.c
@@ -276,7 +276,7 @@ xchk_iallocbt_chunk(
xchk_inobt_chunk_xref_finobt(sc, irec, agino, nr_inodes);
else
xchk_finobt_chunk_xref_inobt(sc, irec, agino, nr_inodes);
- xchk_xref_is_owned_by(sc, agbno, len, &XFS_RMAP_OINFO_INODES);
+ xchk_xref_is_only_owned_by(sc, agbno, len, &XFS_RMAP_OINFO_INODES);
xchk_xref_is_not_shared(sc, agbno, len);
xchk_xref_is_not_cow_staging(sc, agbno, len);
return true;
@@ -428,7 +428,7 @@ xchk_iallocbt_check_cluster(
return 0;
}

- xchk_xref_is_owned_by(bs->sc, agbno, M_IGEO(mp)->blocks_per_cluster,
+ xchk_xref_is_only_owned_by(bs->sc, agbno, M_IGEO(mp)->blocks_per_cluster,
&XFS_RMAP_OINFO_INODES);

/* Grab the inode cluster buffer. */
diff --git a/fs/xfs/scrub/inode.c b/fs/xfs/scrub/inode.c
index 95694eca3851..3b272c86d0ad 100644
--- a/fs/xfs/scrub/inode.c
+++ b/fs/xfs/scrub/inode.c
@@ -556,7 +556,7 @@ xchk_inode_xref(

xchk_xref_is_used_space(sc, agbno, 1);
xchk_inode_xref_finobt(sc, ino);
- xchk_xref_is_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_INODES);
+ xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_INODES);
xchk_xref_is_not_shared(sc, agbno, 1);
xchk_xref_is_not_cow_staging(sc, agbno, 1);
xchk_inode_xref_bmap(sc, dip);
diff --git a/fs/xfs/scrub/rmap.c b/fs/xfs/scrub/rmap.c
index 9ac3bc760d6c..7b0ad8f846ab 100644
--- a/fs/xfs/scrub/rmap.c
+++ b/fs/xfs/scrub/rmap.c
@@ -167,38 +167,29 @@ xchk_rmapbt(
&XFS_RMAP_OINFO_AG, NULL);
}

-/* xref check that the extent is owned by a given owner */
-static inline void
-xchk_xref_check_owner(
+/* xref check that the extent is owned only by a given owner */
+void
+xchk_xref_is_only_owned_by(
struct xfs_scrub *sc,
xfs_agblock_t bno,
xfs_extlen_t len,
- const struct xfs_owner_info *oinfo,
- bool should_have_rmap)
+ const struct xfs_owner_info *oinfo)
{
- bool has_rmap;
+ struct xfs_rmap_matches res;
int error;

if (!sc->sa.rmap_cur || xchk_skip_xref(sc->sm))
return;

- error = xfs_rmap_record_exists(sc->sa.rmap_cur, bno, len, oinfo,
- &has_rmap);
+ error = xfs_rmap_count_owners(sc->sa.rmap_cur, bno, len, oinfo, &res);
if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
return;
- if (has_rmap != should_have_rmap)
+ if (res.matches != 1)
+ xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
+ if (res.badno_matches)
+ xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
+ if (res.nono_matches)
xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
-}
-
-/* xref check that the extent is owned by a given owner */
-void
-xchk_xref_is_owned_by(
- struct xfs_scrub *sc,
- xfs_agblock_t bno,
- xfs_extlen_t len,
- const struct xfs_owner_info *oinfo)
-{
- xchk_xref_check_owner(sc, bno, len, oinfo, true);
}

/* xref check that the extent is not owned by a given owner */
@@ -209,7 +200,19 @@ xchk_xref_is_not_owned_by(
xfs_extlen_t len,
const struct xfs_owner_info *oinfo)
{
- xchk_xref_check_owner(sc, bno, len, oinfo, false);
+ struct xfs_rmap_matches res;
+ int error;
+
+ if (!sc->sa.rmap_cur || xchk_skip_xref(sc->sm))
+ return;
+
+ error = xfs_rmap_count_owners(sc->sa.rmap_cur, bno, len, oinfo, &res);
+ if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
+ return;
+ if (res.matches != 0)
+ xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
+ if (res.badno_matches)
+ xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
}

/* xref check that the extent has no reverse mapping at all */
diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index a331838e22ff..20e74179d8a7 100644
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -156,7 +156,7 @@ void xchk_xref_is_not_inode_chunk(struct xfs_scrub *sc, xfs_agblock_t agbno,
xfs_extlen_t len);
void xchk_xref_is_inode_chunk(struct xfs_scrub *sc, xfs_agblock_t agbno,
xfs_extlen_t len);
-void xchk_xref_is_owned_by(struct xfs_scrub *sc, xfs_agblock_t agbno,
+void xchk_xref_is_only_owned_by(struct xfs_scrub *sc, xfs_agblock_t agbno,
xfs_extlen_t len, const struct xfs_owner_info *oinfo);
void xchk_xref_is_not_owned_by(struct xfs_scrub *sc, xfs_agblock_t agbno,
xfs_extlen_t len, const struct xfs_owner_info *oinfo);